Self-testing functional characteristics of ultrasonic sensors

Abstract

Functional characteristics of an ultrasonic element are self-tested by, in various embodiments, causing the ultrasonic element to emit an ultrasonic signal; detecting the emitted ultrasonic signal substantially simultaneously with its emission; and verifying proper operation of the ultrasonic element based on comparison between a detected ultrasonic signal parameter and a reference parameter.

What is claimed is: 
     
         1 . A method of self-testing functional characteristics of an ultrasonic element, the method comprising:
 causing the ultrasonic element to emit an ultrasonic signal;   detecting the emitted ultrasonic signal substantially simultaneously with its emission; and   verifying proper operation of the ultrasonic element based on comparison between a detected ultrasonic signal parameter and a reference parameter.   
     
     
         2 . The method of  claim 1 , wherein (i) the ultrasonic element is one of a plurality of ultrasonic elements and (ii) the reference parameter is an average of a plurality of signal parameters each associated with one of the ultrasonic elements in proper operation. 
     
     
         3 . The method of  claim 1 , wherein the signal parameter comprises a signal characteristic and the reference parameter comprises a reference characteristic. 
     
     
         4 . The method of  claim 3 , wherein the reference characteristic comprises a rising phase amplitude, a saturated phase amplitude, and a decreasing phase amplitude. 
     
     
         5 . The method of  claim 1 , wherein the signal parameter is a signal amplitude and the reference parameter is a reference amplitude threshold. 
     
     
         6 . The method of  claim 1 , wherein the signal parameter is a time period during which an amplitude of the signal is larger than a voltage threshold and the reference parameter is a reference minimum time period. 
     
     
         7 . The method of  claim 1 , wherein the ultrasonic signal is detected prior to receiving a reflected signal. 
     
     
         8 . A system for self-testing an ultrasonic transducer element using a detector element for receiving ultrasonic signals emitted by the transducer element, the system comprising:
 drive circuitry coupled to the transducer element for causing the transducer element to emit ultrasonic signals; and   a controller for controlling ultrasonic-signal emission and detection by the transducer element and the detector element, respectively, the controller being configured to verify proper operation of the transducer element based on comparison between a detected ultrasonic signal parameter and a reference parameter.   
     
     
         9 . The system of  claim 8 , wherein the transducer element both emits and receives the ultrasonic signals. 
     
     
         10 . The system of  claim 8 , wherein (i) the ultrasonic element is one of a plurality of ultrasonic elements and (ii) the drive circuitry causes a first transducer element to emit the ultrasonic signals and a second transducer element to detect the emitted ultrasonic signals. 
     
     
         11 . The system of  claim 8 , wherein the signal parameter comprises a signal characteristic and the reference parameter comprises a reference characteristic. 
     
     
         12 . The system of  claim 11 , wherein the reference characteristic comprises a rising phase amplitude, a saturated phase amplitude, and a decreasing phase amplitude. 
     
     
         13 . The system of  claim 8 , wherein the signal parameter is a signal amplitude and the reference parameter is a reference amplitude threshold. 
     
     
         14 . The system of  claim 8 , wherein the signal parameter is a time period during which an amplitude of the signal is larger than a voltage threshold and the reference parameter is a reference minimum time period. 
     
     
         15 . The system of  claim 8 , wherein the ultrasonic signal is detected prior to receiving a reflected signal.